Jet augmenter for combustion turbine propulsion plants



Nov. 4, 1947. F. A. M. HEPPNER 2,430,399

JET AUGMENTERFOR COMBUSTION TURBINE PROPULSION PLANTS Filed Sept. 11,1943 3 Sheets-Sheet 1 Nov. 4, 1947. F, M, HE NER 2,430,399

JET AUGMENTER FOR COMBUSTION TURBINE PROPULSION PLANTS 1(IIIIIIIIIIIIIIII //v VE/V'TO R 3 Mai MM.

.7 Ma farm T'TOK/YEY Patented Nov. 4, 1947 JET AUGMENTER FORCOIVIBUSTION TURBINE PROPULSION PLANTS Fritz Albert Max Heppner,Leamington Spa,

England, assignor to Armstrong Siddeley Motors Limited, Coventry,England Application September 11, 1943, Serial No. 502,035 In GreatBritain November 5, 1942 This invention relates to a compoundinternalcombustion turbine plant for jet-propulsion purposes, anon-compound internal-combustion turbine plant being disclosed in PatentNo. 2,416,389, issued February 25, 1947. v

The invention consists in a compound plant having independent compressorrotors which are respectively coupled, for rotation in unison therewith,to rotary turbine sections the blades of which coact with blades on acontra-rotating turbine member which drives the rotary portion of ajet-augmenter.

Preferably the turbine and compressor are of the axial flow type, theturbine preferably being radially outwardly of the compressor, in whichcase the said turbine member can be arranged to be in the form of ashell to surround the compressor or a portion thereof, and to carry therotary jet-augmenter blades externally. Conveniently, too, the flowthrough the compressor is in the opposite direction to that through theturbine.

In the drawings, Figs. 1, 2 and 3 are respectively diagrammatic viewsshowing different arrangements of the compressor, turbine and augmenterthat may be employed in the present invention;

Figs. 4 and 5' are axial sections through the compressor, turbine andaugmenter of two other embodiments of the present invention;

Fig. 5a is a diagram to illustrate the blading and direction of rotationof the embodiment of Fig.

Figs. 6 and 7 are axial sections through the compressor, turbine andaugmenter of yet other embodiments of the present invention.

As far as possible like reference numerals are applied throughout thevarious figures to denote similar parts.

In the construction of Figure 1 there is a stationary shaft 20 on whichare journalled independent rotors 2|, 22 and 23 of a compressor thestationary, coacting, bladed portions of which are carried by a shell[9. The rotors are mechanically coupled to turbine sections 24, 25 and26, respectively. The three turbine sections have blades which coactwith blades 21 on a counterrotating turbine shell 28 carrying externallyjetaugmenter blades 29 which coact with stationary augmenter blades 30.

8 Claims. (01. 6035.6)

ber 32 (comprising in this case a plurality of singl chambers arrangedin a circle round the axis of the plant) before entering the turbine.

As will be well understood, the exhaust of the turbine and the exhaustof the augmenter, as indicated by the arrows, unite to form thepropulsion jet.

In the construction of Figure 2 there is again a stationary shaft 20upon which-are mounted the rotors 2|, 22 and 23 of three compressorsectlons, and a shell IS on which are carried the stationary, coactingblades. The compressor rotors are mechanically coupled to turbinesections 24, 25 and '26 the blades of all of which coact with blade rows21 on a contra-rotating turbine shell 28 which carries externallyet-augmenter blade rows 29 coacting with stationary augmenter blade rows30 carried by shell [9.

Part of the air compressed by the augmenter is delivered to the firstcompressor section 2| through a plurality of tubular members I! andthence to the second and third sections, a indicated by the arrows,after which combustion is effected in the combustion chamber, indicatedat 32 at the tail-end of the plant, the burning gases then travellingwith reversed flow, as shown by the arrows, through a plurality ofcurved pipes I6, connecting passage l8a formed in the annular shell I8,and pipes 3| to the inlet of the turbine, whilst the exhaust of thelatter and the remainder of the air compressed in the augl'nenterconstitute the propulsion jet.

In the construction of Figure 3 there is a series of independent rotarycompressor sections of which only three are shown in full lines, beingmarked 21, 22 and 23, and these are mechanically coupled with turbinesections 24, 25 and 26, respectively. The coacting compressor blade rows34 are stationary, whilst the coacting turbine blad rows 21 are fastwith the shaft 35 and rotate in the direction opposite to that in whichthe turbine sections 24-26 rotate. The shaft 35 carries rotaryjet-augmenter blades 29 which oo- The compressor flow is indicated bythe aract with stationary augmenter blades 30.

It will be observed that the compressor in this case is arranged to beradially outwardly of the turbine, air for the compressor being taken infrom the jet-augmenter through the tubular member I1 and, on leaving thecompressor, being reversed in the combustion chamber, indicated at 32 atthe tail-end of the plant, before entering the turbine. The exhaust fromthe turbine is again reversed in flow, asindicated by the arrows, tojoin the remainder of the air compressed by the augmenter and toconstitute the propulsion Jet.

In the construction of Figure 4; there is again a stationary shaft 20upon which are mounted a number of independent rotary compressorportions of which three are marked 2|, 22 and 23. These are respectivelycoupled with turbine sections 24, 25 and 26 the blades of which coactwith contra-rotating turbine blade rows 21 on a shell 28, The lattercarries externally rows of jetaugmenter blades 29 coacting withstationary augmenter blades 30. Stationary compressor blades 34 aremounted on the shaft 28.

In this construction the air for the compressor is taken in at 36, andafter traversing the compressor it is reversed in the combustionchamber, indicated at 32, before being passed to the turbine.

The outlet from the turbine is passed through passages formed instationary, intake vanes 38 of the augmenter, the latter being hollow,and in due course, as indicated by the arrows, it mingles with thedelivery from the augmenter to constitute the propulsion jet.

The construction of Figure has much in common with that of Figure 4,except that, in Figure 5, in addition to the contra-rotating shell 28there is also contra-rotation between adjacent combined turbine andcompressor blade rows. The blading and direction of rotation areillustrated in Figure 5a.

Thus, it will be observed that there are compressor portions such asthose marked 2|, 22 and 23 respectively coupled with turbine portionssuch as those marked 24, 25 and 26, which all rotate in one direction,being journalled upon the stationary shaft 20, and coacting with theseturbine portions are blades 21 on a counter-rotating shell 28 whichcarries externally the rows of augmenter blades 29 coacting with thestationary augmenter blade rows 38. In addition, there are stationaryturbine blade rows 48 and there are other turbine blade rows such asthose marked 4 I, 42 and 43 respectively coupled to compressor sectionssuch as those marked 44, 45 and 46 rotating in the same direction as theshell 28.

Air for the compressor is taken in at 33, being reversed in thecombustion chamber, indicated at 32 at the tail-end of the plant, beforebeing delivered to the turbine. The exhaust from the latter is again ledthrough stationary intake vanes 38, of the augmenter, which are hollow,as indicated by the arrows, and in due course it mingles with thedelivery from the augmenter, to constitute the propulsion jet.

In the. construction of Figure 6 there are again rotary compressorsections 2|, 22 and 23 journailed upon a stationary shaft 28 andrespectively coupled to turbine portions 24, 25 and 26 the blades ofwhich coact with turbine blade rows 21 carried by a short shell 28adriving rotary augmenter blades 29 coacting with stationary augmenterblades 38, and in this case one of the turbine blade rows 21 is fastwith the row 48 of compressor blades which is journalled upon the shaft20 and rotates in the opposite direction to the compressor sections 2 I,22 and 23. The stationary compressor blades are indicated at 34.

Air for the compressor is introduced at 36 and is reversed in thecombustion chamber, indicated at 32 at the tail-end of the plant, beforebeing delivered to the turbine whilst the exhaust from the latter isagain reversed in flow by passage l4 and mingles with the augmenter airto constitute the propulsion jet.

Substantially the same arrangement is disclosed in Figure 7, except thatthere are two rows 21 of counter-rotating turbine blades which arerespectively coupled to two rows 48 of compressor blades. Furthermore,in this case the exhaust from the turbine is taken through passagesformed in stationary intake vanes 38, of the augmenter, which arehollow, and finally passed through similar passages formed in stationaryoutlet vanes 50 of the augmenter to join the air of the latter andconstitute the propulsion jet. This serves for equalizing thetemperatures of the augmenter air and the turbine exhaust, and therebyincreases the sound speed limit of the mixture in the nozzle. Thepressures of the two fluids when mixing should be substantially thesame, in order to avoid shock, and a small difference in the speeds willcause only negligible losses and in many cases may be advisable. If theaugmenter blades are steep ones, i. e., at negative incidence for thedesigned speed, satisfactory operation will be obtained when climbing.

The constructions of Figures 6 and 7 have much in common with thatdisclosed in the specification accompanying my co-pending patentapplication Serial No. 500,694, filed August 31, 1943.

The plant is short, light and very compact with substantially no unusedspace. It provides for good auxiliary drives and the turbine is shortand efiicient, whilst few labyrinths only are required. The stressing isgood and excellent mixing of the turbine exhaust and augmenter air canbe obtained.

The general theory of the multi-compound engine requires that most ofthe useful energy shall be taken out mechanically, i. e., that the mainpart of the propulsive effort (as regards a jet-pro pulsion plant) shallbe provided by a jet-augmenter. In the latter the incoming air is sloweddown and its pressure, by a ram effect, is increased. After compressionin the augmenter the air is expanded in the jet nozzle. When an aircraftwith such an engine is climbing, however, the ram effect is negligibleand the overall pressure ratio in the augmenter drops considerably andthe jet diameter tends to become too small. This effect would be worseif the jet were supersonic with a diverging nozzle because the jet wouldthen be reduced to the smallest cross-section of the nozzle and noexpansion in the diverging part of the nozzle could take place, inasmuchas owing to the lack of ram pressure the overall pressure ratio in theaugmenter would have dropped. But whereas sound speed is the limit forthe speed of the jet of an augmenter engine, taking into considerationboth climbing and the possibility of regulation, a comparatively highjet speed is desirable to give the augmenter air the maximum amount ofoverall acceleration whereby to avoid too great a percentage of intakelosses. As stated, however, by mixing the hot gases of the turbineexhaust with the augmenter air the sound speed limit in the nozzle isincreased.

The above conditions require a large slowlyrotating augmenter and bydriving this from a contra-rotating turbine shell such as 28 or 28a theturbine can have high relative speed without excessive stresses. Thenecessary reaction torque is preferably provided by the reaction of thewhole compressor, and for a very high compression ratio this is justenough. From desi n considerations this point is very satisfactory withregard to the non-stall condition of a regulation compound engine. Ingeneral, the sound speed and performance conditions appear to excludethe satisfactory use of small-diameter engines because of restriction tomass flow.

It is, therefore, important to keep the overall length short, ratherthan to reduce the diameter of the plant, and, as regards headresistance, it should be noted that all the resistance is skin frictiononly and that no form drag can develop.

What I claim as my invention and desire to secure by Letters Patent ofthe United States is:

1. A compound internal-combustion turbine plant for jet propulsionpurposes including a plurality of independent compressor sectionsthrough which the fluid flows in series, a combustion chambercommunicating with the end compressor section of said series, aplurality of turbine sections arranged in series and communicating withthe outlet of said chamber, said turbine sections being respectivelycoupled to said compressorr sections to drive the same, a turbine memberrotating in the direction opposite to said turbine sections, bladescoacti'ng with all of said turbine sections carried by said member, ajet augmenter including blades driven by said member, a jet duct, meansfor conveying fluid from the end turbine section of said series to said:Iet duct, and means for conveying fluid from said augmenter to saidduct.

2. A turbine plant according to claim 1 in which the turbine member is arotatable shell and the blades driven thereby are mounted externallythereon,

3. A turbine plant according to claim 1 in which the compressor sectionsand the turbine sections are arranged for axial flow of the fluidtherethrough and in which the turbine sections and the compressorsections are arranged at different radii with one surrounding the other.

4. A compound internal-combustion engine plant for jet propulsionpurposes including a plurality of independent compressor sectionsthrough which the fluid flows axially in series, a combustion chambercommunicating with the end compressor section of the series, a pluralityof turbine sections arranged in series for axial 6 flow of the fluidtherethrough and communicating with the outlet of said chamber, saidturbine sections being respectively coupled to said compressor sectionsto drive the same, said turbine sections being disposed radiallyoutwardly of said compressor sections, a shell rotating in the directionopposite to said turbine sections, blades carried internally by saidshell and coacting with blades of all of said turbine sections, a jetaugmenter including blades carried externally by said shell, a jet duct,means for conveying fluid from the end turbine section of said series tosaid jet duct, and means for conveying fluid from said augmenter to saidduct.

5. A turbine plant according to claim 4 in which the means for conveyingfluid from the end turbine section to the jet duct reverses thedirection of flow of the fluid.

6. A turbine plant according to claim 4 in which the means for conveyingfluid from the end turbine section to the jet duct reverses thedirection of flow of the fluid and passes around said augmenter.

7. A turbine plant according to claim 4 in which the augmenter includesstationary vanes having passages therein and the means for conveyingfluid from the end turbine section to the jet duct includes the passagesthrough said stationary vanes.

8. A turbine plant according to claim 4 having between two of saidcompressor sections a further compressor section which is mechanicallycoupled to said shell.

FRITZ ALBERT MAX HEPPNER.

REFERENCES CITED The following references are of record in the me ofthis patent:

UNITED STATES PATENTS

